15题 A是错的,同一个函数不可以有多个返回值
16 B 是错误,重载的方法不可以改变返回值
'seeNum()' in 'com.auskat.demo.ee.Apple.C' clashes with 'seeNum()' in 'com.auskat.demo.ee.Apple'; attempting to use incompatible return type